This invention relates to display devices, and more particularly to getters used in field emission displays (FEDs).
In a typical FED, a cathode has a plurality of conical emitters that addressably and controllably emit electrons, and an anode has a transparent dielectric layer, a transparent conductive layer over the dielectric layer, a grille formed over the conductive layer to define pixel regions, and a phosphor coating applied to the conductive layer in the defined pixel regions. When activated, the emitters emit electrons to the pixel regions, to produce a visible light image. The light at each pixel is controlled by the current in the emitters facing the respective pixel.
The cathode and anode are assembled very close together, e.g., about 200-250 microns, in a package with a vacuum seal, such as a frit glass seal, at or near the perimeter of the anode and cathode. In the small space between the anode and cathode, any residual gases or molecules can cause arcing or shorting. To address this problem, a getter is placed in the display package and is then activated to sorb free molecules. Placement of the getter is problematic, however, because of the small space. In some FEDs, the cathode is mounted between the anode (also referred to as a faceplate) and a backplate; in this case, a getter can be placed in the space between the cathode and the backplate. While saving space, such placement puts the getter away from the space between the cathode and anode where gettering is needed most. In other cases, the getter is placed on the side of the cathode and anode, but such placement increases the width of the display without increasing the screen size.